What is angina? National Heart Lung and Blood Institute website. Available at:
http://www.nhlbi.nih.gov/health/health-topics/topics/angina. Updated June 1, 2011. Accessed June 29, 2015.

What is angina? American Heart and Stroke Association website. Available at:
http://www.heart.org/idc/groups/heart-public/@wcm/@hcm/documents/downloadable/ucm%5F300287.pdf. Published 2012. Accessed June 29, 2015.